Concrete pattern tamper having elastomeric body and neck

ABSTRACT

A tamper for imparting patterns through a die to a pliable surface, most commonly a newly poured concrete structure such as a walkway, is disclosed. In the tamper of this invention its base, including the integrated handle-receiving neck, is formed substantial entirely of an elastomeric material with a defined hardness, thus reducing or eliminating the severe physical shocks which are caused when a tamper strikes a die or a concrete surface at an off-line angle. The elastomer material must have a Durometer hardness in range of 50-95, preferably 70-95 and more preferably 85-95 as measured on the Shore A hardness scale. Numerous elastomers are suitable for use; polyurethane polymers are preferred. A single type of elastomer may be used for the entire base or two or more elastomers may be conjoined and assembled to form the base.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation-in-part of design patent applicationSer. No. 29/236,450, filed on Aug. 16, 2005, entitled “TAMPER”.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention herein relates to apparatus for imparting decorativesurface patterns to pliable structures, primarily concrete pavements andwalls.

2. Background of the Invention

Imparting of decorative patterns to the surface of newly formed concretestructures such as patios, swimming pool decks, walkways, driveways,walls and the like is a well-established industry. In many installationsthe pattern is formed in a surface of the wet concrete body by rollingor tamping with a machine-operated embossing pattern die. However, innumerous other installations machine embossment is either not practicalor not desired. In such installations the embossment is done by a workerusing a hand-held tamper. The tamper may have the pattern embossing diemounted on it so that the worker directly embosses the surface, or theremay be a sheet-like pattern die laid on the wet concrete surface, andthe worker then uses the tamper to tamp the back of the die to embossthe die's pattern into the surface. In either case the die isconstructed such that the pattern to be imparted to the surface isformed as protrusions extending outwardly from a surface of the die. Theheight of the protrusions determines the depth to which the pattern isimparted to (embossed into) the concrete surface.

Hand tampers have conventionally been made of a rigid material, formerlywood but most commonly now steel. FIG. 1 illustrates a typicalcommercial steel tamper 2. The tamper 2 consists of a base plate 4,usually braced with ribs 6, with an integrated rigid neck 8 into whichan elongated handle 10 is inserted. The handle 10 is rigidly attached tothe neck 8 either by screwing or welding the handle into the neck or byhaving the handle and base/neck formed integrally during manufacture.These rigid tampers are difficult for workers to use comfortably and canbe damaging to the concrete surface in use. If the worker does notstrike the concrete surface or pattern die with the tamper heldprecisely perpendicular to the surface or die, the tamper base willrotate to a horizontal position as it strikes the surface or die andwill jerk the handle hard against the worker's hands. The impact isoften sufficient to make the worker lose a grip on the handle.Simultaneously, as the base hits the surface/die the base can push intothe surface more deeply at one edge than the other, thus making theembossment uneven. In some cases tamper manufacturers have coated thesteel bases with a thin elastomeric or plastic layer but that has notsignificantly relieved the problems, particularly the problem of thehandle's impact on the worker's hands and arms.

One attempt by the prior art to alleviate these problems with tampers isillustrated in FIG. 2. In this type of tamper 12 the base 14 is madepartially or entirely of an elastomeric material into which is embeddeda small metal plate 16. The handle 18 is attached to the metal plate 16usually by a bolt or screw (not shown) or the handle and plate areformed integrally and the handle/plate assembly is embedded into thetamper base 14 when the base is moulded. This type of tamper has beenfound to be only minimally easier to use than the conventional steeltampers. Only minimal flexibility is imparted to the handle by theembedded plate structure, so there is still substantial impact to theworker's hands and arms if the tamper is not held exactly on-line whenstriking the surface or die. Further, if the striking is sufficientlyoff-line, there is a tendency for the handle/plate assembly to tear freeof the elastomeric base, thus rendering both the handle and the baseunusable.

It is evident that the hand/arm impact problems result in rapid workerfatigue when using hand tampers. This in turn significantly slows theprogress of embossment jobs and/or requires that a contactor hireadditional tamper workers so that the workers doing the tamping can berelieved frequently.

It is therefore an object of this invention to provide for a hand tamperhaving a structure with a degree of flexibility sufficient to reduce oreliminate the hand/arm impacts for workers using the tamper, reduce oravoid damage to concrete surfaces from off-line strikes of the tamper,and yet have sufficient stiffness and rigidity in the structure suchthat good imparting of the patterns to the concrete surface is obtainedconsistently and quickly.

BRIEF SUMMARY OF THE INVENTION

The invention herein is a novel tamper for imparting patterns through adie to a pliable surface, most commonly a newly poured concretestructure such as a walkway, patio, wall or the like. The tamper of thisinvention is unique in that its base, including the integratedhandle-receiving neck, is formed substantial entirely of an elastomericmaterial with a defined hardness. The elastomeric material allows thecontact portion and the neck, although integrated together into thebase, to move independently. This independent movement, although small,is sufficient to enable the tamper to reduce and often eliminate thesevere physical shocks and jerks which are present in prior art tamperswhen a tamper strikes a die or a concrete surface at an off-line angle(i.e., with the contact surface of the tamper not exactly parallel tothe die or surface). The flexibility of this independent movementpermitted by the elastomeric material thus greatly reduces the stressesand impacts transferred to the worker using the tamper and also reducesdamage to the surface being patterned.

In the present invention the elastomer material must have a Durometerhardness in range of 50-95, preferably 70-95 and more preferably 85-95,as measured on the Shore A hardness scale. Numerous elastomers aresuitable for use; polyurethane polymers are preferred. A single type ofelastomer may be used for the entire base or two or more elastomers maybe conjoined and assembled to form the base.

The tamper may itself have embossing means on the bottom contact surfaceof the body, but preferably has a flat bottom contact surface and isused to strike the outer side (back) of a separate embossing die sheet.The underside (front) of the die has the embossing structure from whichthe pattern is imparted to the pliable concrete surface when the die isstruck by the tamper.

These and numerous other features and properties of the tamper of thisinvention will be described in more detail below.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a prior art tamping device.

FIG. 2 is an elevation view, partially in section, of another prior arttamping device.

FIG. 3 is a centerline elevation view, partially in section, of a tamperof the present invention.

FIG. 4 is a perspective view from the front and above a tamper of thepresent invention, showing the device as normally assembled.

FIG. 5 is a cross-sectional view of the tamper of FIG. 3, taken on theline 5-5 in FIG. 3, and also illustrates the use of different elastomersin the device.

FIG. 6 is an elevation view, partially in section, of a mould useful inthe manufacture of the tamper of this invention.

FIG. 7 is a diagrammatic elevation view illustrating the flexibleproperties of the tamper of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

The tamper of the present invention is best understood by reference toFIGS. 3-7 of the drawings.

Considering first FIGS. 3 and 4, it will be seen that the tamper 20comprises a base 22 which includes a neck 24 which has a deep recess 26into which is seated an elongated handle 28. It is a critical feature ofthe present invention that the tamper base 22 including the neck 24 isformed substantially entirely of an elastomeric material of a stiffnesssufficient to provide the appropriate combination of flexibility andrigidity to substantially reduce or eliminate the impact and damagetendencies of the prior art devices. The elastomeric material and itsstiffness will be defined further below. The base 22 can be consideredas having two and preferably three portions: a broad generally flatcontact body 23 the bottom surface 25 of which makes the operativecontact with the concrete 64 or with the die 62, an optional raisedcentral portion 32 and a neck 24. The contact body 23 will be formed asa wide flat member, preferably rectangular or square with dimensions onthe order of about 12″-16″ [30-40 cm] on each long side and a thicknesson the order of 2″-4″ [5-10 cm]. The contact body 23 portion of the base22 may be made larger or smaller as desired, or made in a circular, ovalor other flat shape, but it has been found that the preferred dimensionsand shapes normally result in the optimum combination of workerefficiency and speed of completion of embossing projects.

It is preferred that a stiff plate 30 be embedded in the interior of thecontact body 23 portion of the base 22 to enhance the rigidity of thecontact body 23 portion of the base and to add weight to enhance theforce imparted by the tamper to the die during embossment. The plate maybe made of metal such as steel or aluminum or of a heavy plasticmaterial. The dimensions of the plate 30 are not critical, but commonlythe plate 30 thickness will be on the order of ¼″-½″ [6-12 mm]). Thereshould be a sufficient thickness of elastomeric material surrounding andabutting the plate 30 that the use of the tamper does not cause theplate 30 to abrade and cut through the elastomeric material of the base22. The plate 30 can conveniently be incorporated into the base 22during moulding of the tamper, as will be described below, or anincision can be made in the base 22 after moulding, the plate 30inserted and the incision closed and sealed, as by an adhesive. Thelatter technique is not preferred, however, as the incision, thoughsealed, remains as a potential point of weakness and failure of thetamper during prolonged use.

The tamper base 22 may have integrated into its structure a raisedcentral portion 32. This portion enhances the attachment of handle 28 tothe base 22 in that it allows for a deeper recess 26 and also provides alarger flexible volume of elastomeric material to absorb and reduce theimpact effect of off-line strikes of the tamper. As illustrated in FIG.5, the raised portion can be formed of a different elastomeric materialthan is used in the lower portion of the base 22. The two elastomers maybe adhered during the moulding process, as described below, or they maybe formed separately and then adhered by a suitable adhesive at thesurface junction 34 of the two elastomers. Where there are twoelastomers the neck 24 is more conveniently formed of the sameelastomeric material as is the raised portion 32, although a base 22 ofone elastomer may be formed with an extended neck 24 integrated with andextending upwardly from it, with the raised portion being formed of theother elastomer as an annulus through which the neck 24 extends, withthe two elastomers then being adhesively bonded.

Extending upwardly from base 22 and/or raised portion 32 is neck 24. Theneck is formed as a hollow cylinder usually having a height of about3″-6″ [7-15 cm]. The diameter will be determined by the diameter of thehandle 28 (usually about 1″-1½″ [25-35 mm]) plus twice the wallthickness of the neck (usually about ¼″-½″ [6-12 mm]). The axial recess26 will normally extend through the length of the neck 24 and into theraised portion 32 (if any) of base 22, but should not be so deep as toleave an insufficient thickness of elastomer between the bottom end ofthe handle 28 and the top surface of any internal plate 30. A hole 36extends laterally through opposite sides of the wall of neck 24 with acorresponding co-axial hole 38 through handle 28 to allow securing ofhandle 28 to the tamper base 22. A securing pin 40 is removably insertedthrough holes 36/38 when the handle 28 is inserted into the recess 26 tolock the handle 28 into the recess 26. The pin 40 has a head 42 on oneend to prevent the pin 40 being pushed through the holes 36/38. Attachedto head 42 is one end of an elongated wire 44 used to retain pin 40 inplace during use of the tamper. The wire 44 is sufficiently long to loophalfway around the neck 24 and has at its opposite end a loop 46 whichfits over the end 48 of pin 40 opposite from the head 42. The wire 44 isa spring wire which is sufficiently rigid to maintain its curved shapebut has a small amount of flexibility to enable it to be stretched toallow the loop 46 to pass over the end 48 of pin 40 and then spring backtoward neck 24 to prevent loop 46 from falling off of pin 40 when thetamper is in use.

The handle 28 is conventional and may be of any convenient material,such as wood, plastic, hard elastomer or metal.

The elastomeric material or materials used for the base 22, raisedportion 32 and neck 24 of the tamper may be of any convenient natural orsynthetic rubber or other elastomer. Elastomers are well-known,extensively described in the literature and widely availablecommercially. Typical of the suitable materials are polyurethanes,styrene-butadiene copolymers, cross-linked rubbers and butyl rubbers, ofwhich the polyurethane polymers are preferred. It has been found that tohave the requisite combination of stiffness and flexibility to beeffective in the products of this invention an elastomeric material musthave a Durometer hardness in the range of 50-95, preferably 70-95 andmore preferably 85-95, as measured on the Shore A scale. Those skilledin the art will readily be able to select suitable elastomers havingacceptable hardnesses from the many commercial products available;polyurethane polymers of Shore Durometer A hardness of 85-95 which arecommercially available from Innovative Polymer Systems (RanchoCucamonga, Calif.) have been found to be quite satisfactory.

The tamper of the present invention is most conveniently made bymoulding of the elastomeric material. FIG. 6 illustrates incross-section a typical mould which can be used for this process. Themould 50 is mounted on a support structure 52 which is sufficientlysturdy to support the weight of the mould 50, the quantity ofelastomeric material, and any plate 30 which is to be integrated intothe product. An open wood structure of dimensional lumber framing hasbeen found satisfactory. The inner surface of the cavity 54 is of coursethe “negative” of the outer surface of the base 22, with the open top 55of the cavity 54 bordering the surface of liquid elastomer poured intothe cavity which cures to form the bottom contact surface 25 of thetamper. Within the mould cavity 54 is a central plug 56 which serves tomould the recess 26 in neck 24. In FIG. 6 the plug 56 is illustrated asbeing integral with the rest of the mould body 50. However, as analternative the mould body 50 may have a hole 58 formed in it throughwhich a separate plug 56 can be inserted, to allow for moulding oftamper bases with different diameters of recesses 26. Such removableplugs 56 may be secured for use in any convenient way, such as by beingscrewed into hole 58 using cooperating threads on the hole 58 and plug56, or by having a small plate attached to one end of plug 56 with theplate being bolted or screwed to the underside of mould body 50 asillustrated at 60.

The tamper base is then formed in a conventional moulding procedure bypouring the elastomeric material into the mould cavity 54 and curing thematerial to the requisite Durometer hardness by known means, commonlythermally or by inclusion in the poured material of chemical curingcatalysts. If a plate 30 is to be incorporated it can be laid into themould at the appropriate point in the pouring process. Similarly, ifthere are to be two elastomers used, they can be poured in and curedsequentially in any convenient known manner. All such mouldingtechniques and procedures are well known to those skilled in the art anddo not need further elaboration here.

It is preferred that edges and corners of the base 22 be slightlyrounded (radiused) as illustrated in the Figures, to prevent unduetearing or abrading of the elastomeric materials and to lessen theformation of extraneous grooves or lines in the pliable surface. Suchrounding is easily accomplished during moulding, since mould cavitiesare normally formed with radiused corners and joints to facilitatematerial flow within the mould and avoid gaps in the moulded bodies. Tothe extent that such rounding does not occur automatically by moulding,corners or edges may if desired be rounded manually as by routing,planing, sanding, thermal melting or similar techniques well known tothose skilled in the art.

FIG. 7 illustrates graphically the unique properties of the presentinvention. In FIG. 7 the tamper 20 is illustrated as being used toemboss a surface pattern into a newly laid concrete structure 64, suchas a patio or walkway, using a conventional pattern die 62. The industrypractice is for a worker to place the die 62 on the concrete 64 with thepattern side of the die 62 facing downward where the pattern is to beembossed, and then press or pound the tamper 20 onto the back side ofthe die 62 to force the pattern structure of the die into the concretesurface. Once the pattern is embossed and the concrete surface issufficiently stable to maintain the embossed pattern, the die 62 isremoved, cleaned and can be reused. It is common to use a number ofabutting dies simultaneously to enable a large-scale pattern to beembossed over a wide surface area of the concrete 64 at one time, byhaving one worker repeatedly tamp all of the dies in rapid sequence orby having several workers tamp individual dies or groups of dies. Ineach case, however, the tamping procedure is the same. The worker willraise the tamper 20 above the outward (non-pattern) side of the die 62and bring it down to strike the die and force the opposite pattern sideinto the pliable concrete surface 64. In order for the pattern to beproperly transferred to the concrete surface, the tamper base 22 shouldbe parallel to the back of the die 62 when it strikes the die, whichmeans that the tamper handle 28 should be perpendicular to the die 62and concrete surface 64 as the tamper descends. However, too often theworker does not hold the handle 28 exactly perpendicular to the die andconcrete surface when tamping, as illustrated by examples of differenthandle positions indicated at 28′ and 28″. This causes the base 22 tostrike the die 62 at an angle as illustrated at 22′ (corresponding tohandle position 28′). In the prior art tampers this mis-alignment oroff-line striking necessarily causes the handle—being rigidly attachedto the base—to suddenly jerk from, for instance, position 28′ toposition 28 as the base 22 pivots from position 22′ to position 22 uponstriking the die 62 with the concrete surface 64 underneath. This suddenjerking action at the minimum imparts a sharp impact to the worker'shands and arms, causing discomfort to the worker and stress to theworker's arm and hand muscles and joints. Not infrequently the jerk issufficiently strong to rip the handle 28 out of the worker's grip, againcausing discomfort and stress, and often also causing damage to thetamper, the die and/or the concrete surface as the handle and tampermoved or fell. Even if there is no immediate injury to the worker or thedie or concrete, such jerking actions, repeated numerous times, resultover time in chronic discomfort to the worker.

In the present tamper, however, these problems and dangerous situationsare substantially reduced or eliminated by the flexibility of theelastomeric neck 24 of the tamper integrated elastomeric structure ofthe base 22. When the worker brings a tamper 20 of the present inventiondownward to strike the die 62, being slightly off-line is readilycompensated for. The flexible neck 24 allows the handle 28 and the base22 to move independently, such that the base 22 can self-level as itcontacts the die even while the handle 28 is in the off-line angledposition (such as 28′ or 28″), so that the handle 28 is not forced tomove in the worker's grip by the self-leveling of the base 22. Theworker thus is not subjected to sudden jerking of the handle 28 andresultant stress to hands and arms. Rather as the base 22 self-levels,the worker can in a smooth, controlled and easy movement bring thehandle 28 to a position perpendicular to the die by movement of theflexible neck from position 24′ to position 24 so that the tamper canforce the die pattern properly into the concrete surface 64. Over thecourse of a work period the worker thus becomes much less fatigued andcan maintain a high level of performance throughout the work period.Further, the patterns embossed are of much more consistent quality, dueto the self-leveling ability of the tamper base 22. These properties andresults have not previously been available in any of the prior artproducts.

Throughout this specification the pliable surface to which the patternis to be imparted has been described as “concrete.” It is to beunderstood, however, that the tamper of this invention and itsassociated die or dies may be used to impart a pattern to any pliablesurface which can retain the imparted pattern. While bodies andstructures made of conventional concrete materials are the most commonsubjects for such patterning (while they are newly poured and stillpliable), the use of the tamper invention herein is not limited toworking of concrete. Other durable materials which can be embossedduring a pliable stage, such as various terrazzo, asphalt, hard clay,moulded polymeric or mineral particulate boards and the like are alsoequivalent to concrete for the purposes of this invention. Therefore theterm “concrete” is used herein for brevity, and the applications of thetamper of this invention are not to be limited solely to use withconventional concrete materials but may be used with any equivalentpliable surface material where substantially equivalent imparting ofpatterns is desired. In addition, it will be recognized that the tampermay be used, as is common in laying of concrete, to tamp the dirt ontowhich the concrete (or base layer beneath the concrete) is to be laid.

It will be evident that there are numerous other embodiments of thetamper of this invention which are not expressly discussed above but areclearly within the scope and spirit of the invention. The abovedescription is therefore to be considered exemplary only, and the actualscope of the invention is to be determined solely from the appendedclaims.

I claim:
 1. A tamper for imparting patterns into a pliable surfacecomprising a base including an elongated neck having a hollowcylindrical recess for receiving a generally cylindrical handle, saidhandle adapted for a standing person to strike an embossing die with thetamper for imparting patterns into a pliable surface, and said base andsaid neck being formed substantially entirely of a flexible elastomericmaterial having a Shore A Durometer hardness in the range of 50-95.
 2. Atamper as in claim 1 wherein said elastomeric material has a Shore ADurometer hardness in the range of 70-95.
 3. A tamper as in claim 2wherein said elastomeric material has a Shore A Durometer hardness inthe range of 85-95.
 4. A tamper as in claim 1 further comprising saidmember being a stiff plate.
 5. A tamper as in claim 1 wherein saidelastomeric material comprises an assemblage of a plurality ofelastorners.
 6. A tamper as in claim 5 wherein said assemblage comprisesindividual elastomers disposed separately within said base in abuttingand conjoined relationship.
 7. A tamper as in claim 1 further comprisingsecuring means in said neck for securing within said neck a handlereceived in said recess.
 8. A tamper as in claim 7 wherein said handlehas an aperture therethrough and said securing means comprises anaperture in a wall of said neck which aligns with said aperture in saidhandle and a pin removably extending through thus-aligned apertures. 9.A tamper as in claim 8 further comprising retaining means on said pin toreleasably retain said pin disposed through said thus-aligned apertures.10. A tamper as in claim 1 wherein said elastomeric material comprises apolyurethane polymer.
 11. A tamper as in claim 1 wherein said basecomprises a generally flat contact body and said neck.
 12. A tamper asin claim 11 wherein said base comprises said generally flat contact bodyand said neck and disposed therebetween a central raised portionabutting both.
 13. A tamper as in claim 12 further comprising saidcontact body and said central raised portion being formed of differentelastomers which are conjoined at an abutting surface.
 14. A mould forformation of said tamper as in claim 1, said mould comprising a cavityhaving a boundary surface configuration which is a negative of a surfaceconfiguration of said tamper base.
 15. A mould as in claim 14 furthercomprising a plug having a surface configuration which is a negative ofan inner surface configuration of said recess.
 16. A mould as in claim15 further comprising said plug being removable from said mould. 17.Apparatus for imparting a pattern to a pliable surface comprising atamper as in claim 1 and a die having a transferable patternincorporated therein, said die being placeable against said surface,whereby when said die is so placed and struck by said tamper, saidpattern is imparted to said surface.
 18. Apparatus as in claim 17wherein said pattern is incorporated into said die by a surface of saiddie having said pattern formed as protrusions extending from saidsurface.